As minister-plenipotentiary at Cassel, between the years 1804 and 1806, he took a prominent share in the formation of the confederation of the Rhine; and after the battle of Jena he returned to Prussia as the administrator of the public domains and finances.
During the Hundred Days he once more entered Napoleon's service, and, after the Battle of Waterloo, as minister of foreign affairs under the executive commission, it was he who signed the Convention of St.
[2] Bignon did not re-enter public life until 1817 when he was elected to the chamber of deputies, in which he sat until 1830, consistent in his opposition to the reactionary policy of successive governments.
But the idea of making him responsible for the foreign policy of France could not be realized owing to the necessity under which Louis Philippe lay of courting the goodwill of the powers, whom Bignon had offended by his outspoken writings.
[2] Elected deputy in 1831[3] and member of the chamber of peers in 1839, he withdrew for the most part from politics to devote himself to his great work, the Histoire de France sous Napoleon (10 vols.